In many cases, two vehicle parts are joined together by means of a screw connection. In order to simplify the manufacture of the screw connection as much as possible, the insertion holes are to some extent oversized in relation to the screws. The oversized insertion hole makes it possible to tighten the screw into the thread even when the vehicle part exhibiting the insertion hole is not positioned exactly in relation to the vehicle part having the thread. Depending on the vehicle parts involved, the inexact positioning can lead to functional limitations and/or a negative aesthetic and qualitative impression. The latter case is encountered in particular for visible vehicle parts, and manifested in an irregular gap width, for example. However, if the objective is to keep assembly simple while at the same time achieving a precise positioning of the two vehicle parts to be joined together, positioning pins are used in addition to the screw connections. For example, the positioning pin is arranged on the first vehicle part, and usually exhibits a conical section to simplify centering and/or positioning. While assembling the vehicle parts, the first vehicle part is moved closer to the second vehicle part. Once a specific distance has been dropped below, the positioning pin interacts with a positioning and/or centering section of the second vehicle part, for example with an edge, a borehole or a recess. In this way, the first vehicle part is centered and positioned relative to the second vehicle part. After the two vehicle parts have been positioned relative to each other, the two vehicle parts can be screwed together.
Conventional positioning pins exhibit a cruciform cross section. The cruciform cross section is arranged in such a way that the positioning and/or centering section glides along only one sliding surface of one of the four cross flanks during assembly. Since the positioning and/or centering section often exhibits sharp edges, in particular given vehicle parts made out of sheet metal, there is a danger that the positioning pins will be severed or broken off while detaching and fastening the two vehicle parts from or to each other, in particular when the worker applies a relatively high pressure to the first vehicle part. As a consequence, the positioning pin can no longer realize its function. For example, it may become necessary to detach and refasten the two vehicle parts in the event of repairs. The more often the two vehicle parts are detached from each other and rejoined with each other, the greater the danger of the positioning pin being broken off or damaged. If the positioning pin fails, the first vehicle part must be changed out completely, so as to ensure that both vehicle parts are precisely positioned relative to each other. This results in an additional expenditure of time and money.